Pressure-cylinder for engines.



H. L. HURD.

PRESSURE CYLINDER FOR ENGINES.

APPLICATION men JAN-4, 1913.

1,145,065, Patented July 6,1915.

a i w 25 0 Z;

4; a 8 P 56' 6' M rinrrnn @llATE earner orriea HENRY L. HURD, or BE ERLY, MASSACHUSETTS.

PRESSURE-CYLINDER FOR ENGINES.

Original application Specification of Letters Patent.

filed January 10, 1911, Serial No. 981,268. Divided and this application filed January 4:, 1913. Serial No. 740,106.

To all whom it may concern:

Be it known that I, HENRY L. HURD, a citizen of the United States, residing at Beverly, county of Essex, State of Massachusetts, have invented a certain new and useful Improvement in Pressure-Cylinders for Engines, of which the following is a specification, reference being had therein to the accompanying drawings.

The invention relates to an improvement in pressure cylinders for engines.

The invention is intended for application to use for controlling link motion engines in which the link can be thrown, or for any movement oif of the center which should go back to the central point and stop.

The object of the invention is to actuate the piston in either direction from the center of the cylinder toward the end and to cause it to automatically return to the center and stop whether the cylinder is in either a vertical or horizontal plane.

The invention will be fully understood from the following description taken in connection with the accompanying drawings, and the novel features will be pointed out and clearly defined in the claims at the close of the specification.

In the drawings: Figure 1 is a sectional elevation of a cylinder embodying the invention, showing the piston in central position. Fig. 2 is a sectional elevation of the cylinder showing the piston moved from the central position shown in Fig. 1. Fig. 3 is a cross section through the cylinder on line 33 of Fig. 2.

In the drawings,1 represents a cylinder within which is a piston 2 which is normally at the center and which is reciprocable within the cylinder toward either end and back to the center. A piston rod 3 connected with the piston passes through one head of the cylinder, the head being provided with a stufling box through which the piston rod passes. Connected with the cylinder 1 is a steam chest 1 to which steam is supplied through a pipe 5. Leading from the steam chest 4 into the cylinder 1 is a port 6 to admit steam into the cylinder at or near one end thereof on one side of the piston, and aport 7 leads from the steam chest into the other end of the cylinder. Leading from the cylinder to the steam chest is an exhaust port 8 which cushions the piston when the piston moves to the lefthand end of the cylinder, as viewed in Fig. 1, and leading from the cylinder to the steam chest is an exhaust port 9 which cushions the piston when the piston moves to the right-hand end of the cylinder, as viewed in Fig. 1.

Within the steam chest is a balanced D slide valve 10 which slides on the face of the steam chest. Within the slide valve are two exhaust cavities 1112 which respectively. connect by means of exhaust passages 13 and 14L with an exhaust pipe 15 leading to the atmosphere. The slide valve 10 is provided with valve stem 16 which passes through the steam chest and may be manually operated from the outside. Any suitable form of balanced connection of well known character may be employed. As shown in the drawings, a pendulum lever 22 is pivotally connected on its upper end at 23 to a fixed support 24, the lower end of said leverbeing pivotally connected with the stem 16 of the D slide valve through an elongated slot 26. A weight 25 is secured to the lever 22 which tends to hold the lever 22 plumb, and which, when the stem 16 of the valve is released after being moved to the right or to the left from the central position shown in Fig. 1, will swing back to plumb position moving the D slide valve back to central position. Leading through the side of the cylinder are two steam ports 17 connecting with an opening 18 to the atmosphere at the middle of the cylinder. The opening 18 is preferably smaller than the inlets 6 and 7 and isconstantly open.

lVhen the slide valve 10 is in the central position as shown in Fig. 1, the admission ports .6 and 7 are both partly open and the exhaust ports 8 and 9 are both closed and the piston 2 is in its central position. If it is desired to move the piston toward the right-hand end of the cylinder, as in Fig. 2, in which it is shown part way toward the end, the valve 10 should be moved to the right from the position shown in Fig. 1 by means of the valve stem 16 which will be operated by hand of the operator at such time as he desires to move the piston. By this movement of the valve stem 16 the slide valve 10 is moved whereby the steam passage 6 is opened fully and the steam passage 7 is closed and the exhaust passage 9 is opened to the atmosphere through the exhaust cavity 12 and the exhaust passage 14. This relieves the pressure from the right-hand end of the piston 2 so that the piston will be moved to the right-hand end of the cylinder by the pressure on the lefthand end. The relief outlet 18 being of smaller diameter than the inlet 6 there will be pressure enough in the left-hand chamber of the cylinder to swing the piston 2 to the right. The relief ports 17 and 18' being left open, the steam in the left hand end of the cylinder will gradually pass out and reduce the pressure. As soon as the stem '16 is released after the valve 10 has been moved to the right by hand, as already described, the weight 25 will automatically swing back to plumb, thereby moving back the stem 16 and moving the valve 10 back to its central position as shown in Fig. 1, so that steam ports 6 and 7 will both partly open, and admit pressure to the cylinder on both sides of the piston 2. By reason, however, of the exhaust ports 17, 18, the pressure on the left-hand end of the piston will be released so that the pressure on the right-hand end of the piston 2 will drive the piston back to the center. The movement of the piston to the center will be slowed down toward the end of its movement by reason of the piston rings closing successively the openings 17 17. The piston will remain at the center with the pressure equalized until the slide valve is again operated by hand. If it is desired to drive the piston to the right again, the relief valve 27 should be closed and the rod 16 will be again pulled to the right, as already described. If it is desired to drive the piston to the left the slide valve 10 will be moved by hand as already described farther to the left so as to close the steam passage 6 and fully open the steam passage 7, thus bringing the pressure against the right-hand end of the piston and exhausting the pressure on the left-hand end of the piston through the exhaust cavity 11 and exhaust passages l315. Then the hand is released from the rod 16 the slide valve 10 will be brought back to the center again automatically, as already described, by reason of the balanced connection, and the pressure upon the right-hand end of the piston will be exhausted through ports 17,18,allowing the pressure which comes in through the lead passage in the partly opened inlet 6 to drive the piston back to center where it will again stop, as already'explained.

The number of the exhaust passages 17 will depend upon the size of the cylinder. For a small size cylinder one passage may be sufiicient. The exact number is not essential.

19 represents the cross head with which the piston rod 3 is connected, and 20 represents a guide rod on which the cross-head 19. slides for the purpose of steadying.

21 represents a link connected with the results are obtained by so constructing and proportioning the parts that the link 21 will move at each stroke far enough to swing the crank 27 through an arc'of about 50 degrees. The operation of a throttle valve, however, is only one form of adaptation of the invention. It is obvious that my invention can be utilized to drive various forms of apparatus other than a throttle valve in which reciprocating movement is desired by making suitable connection with the link 21.

The reason for providing the cylinder with separate exhaust and separate steam ports at each end of the cylinder is so that when the piston closes one of the exhaust ports the steam which is thereby held acts as a cushion to the piston on that end of the cylinder.

While it is possible to operate the piston so that it can-be brought back to center without the use of exhaust ports, yet the exhaust ports render the device much more efficient, especially in speed. 7

One of the uses to which my invention may be applied is in connection with engines employed in operating trolleyboom swingers for unloading cargoes, such for instance as shown in Patent No. 981,268, issued to me January 10, 1911;

vVhat I claim is:

1. A cylinder, a piston which is normally at the center of the cylinder and is movable within said cylinder toward and fromeither end, a rod connected with said piston and extending through one of the h'eads'of the cylinder, means for admitting fluid pressure to and means for exhausting it from said cylinder at opposite ends thereof, means whereby when the fluid pressure is admitted at one end it may be exhausted at the other end whereby said piston is recipro'cated in either direction, a relief port which is closed by the piston when. at the center and which is opened by movement of the piston away from center thereby automatically relieving the pressure from that side of the piston which is toward the center and whereby the pressure on the other side drives the piston back to the center.

2. A cylinder, a piston which is normally at the center of the cylinder and is movable within said cylinder, a rod which is connected with said piston and extends through one of the heads of the cylinder, a source of fluid pressure having connection with both ends of said cylinder, exhaust ports at each end of said cylinder, valve mechanism which controls the admission to and exhaust from both ends of said cylinder, said valve being normally in position where it closes the exhaust ports at both ends and leaves open the inlets at both ends, thereby equalizing the pressure and retaining the piston at the center, means whereby at the will of the operator said valve mechanism may be operated so that fluid pressure may be admitted to either end and shut off from the other end, and the exhaust opened from that end from which the admission is shut off and closed from the other end whereby the said piston is moved from the center toward the opposite end from that in which the inlet port is open and means whereby when the said valve has been moved to either end it is immediately and automatically moved back to center where it closes both exhaust ports and leaves open the inlet ports at both ends and thus equalizes the pressure which thus holds the piston at the center.

3. A cylinder, a piston which is normally at the center of the cylinder and is movable within said cylinder, a rod which is connected with said piston and extends through one of the heads of the cylinder, a source of fluid pressure having connection with both ends of said cylinder, exhaust ports at each end of said cylinder, a relief port at the center which is closed by the piston when at the center and which is opened by movement of the piston away from the center, valve mechanism which controls the admission to and exhaust from both ends of said cylinder, said valve being normally in position where it closes the exhaust ports at both ends and leaves open the inlets at both ends, thereby equalizing the pressure and retaining the piston at the center, means whereby at the will of the operator said valve mechanism may be operated so that fluid pressure is admitted to either end and shut ofltfrom the other end, and the exhaust is opened from that end which is shut off and closed from the other end whereby the said piston is moved from the center toward the opposite end from that in which the inlet port is open, and means whereby when the said valve has been moved to either end it is immediately and automatically moved back to center where it closes both exhaust ports and leaves open the inlet ports at both ends and thus equalizes the pressure and retains the piston at the center.

i. A cylinder, a piston movable within said cylinder, a piston rod connected with said piston and extending through one of the heads of the cylinder, a steam chest having a steam inlet thereto and having steam passages leading into opposite ends of the cylinder, the cylinder having separate exhaust ports leading back to the steam chest, said steam chest having two separate exhaust passages leading to the outside atmosphere, valve mechanism which is adapted to open and close said steam and exhaust ports, means whereby the valve mechanism may be operated to open the inlet port and the exhaust port connecting the steam chest with one end of the cylinder and to close the inlet and open the exhaust to the other end of the cylinder and also adapted to open both the inlet ports and close both the exhaust ports, and a relief passage at the middle of the cylinder which is closed by the piston when the piston is in its central position and which is opened when the piston moves from the center to either end, said valve being normally at the center position closing both exhaust ports and leaving open both inlet ports, and means for automatically moving said valve back to said central position immediately after it has moved to either end of the cylinder.

5. A cylinder, a piston movable within said cylinder, means for admitting fluid pressure to and means for exhausting it from said cylinder at opposite ends thereof, means whereby vwhen the fluid pressure is admitted at one end it may be exhausted at the other end, whereby said piston is moved in either direction, said cylinder having a relief passage which is closed by the piston when at the center and which is opened by the movement of the piston away from the center thereby relieving the pressure from that side of the piston which is toward the center, whereby the pressure on the other side drives the piston back to the center.

6. A cylinder, a piston movable within said cylinder, means for admitting fluid pressure to and means for exhausting it from said cvlinder at opposite ends thereof, means whereby when the fluid pressure is admitted at one end it may be exhausted at the other end, whereby said piston is moved in either direction, said cylinder having a relief passage which when the piston is away from the center relieves the pressure from that side of the piston which is toward the center, whereby the pressure on the other side drives the piston to the center, said relief passage being closed by the piston when it is at the center.

In testimony whereof I aflix my signature, in presence of two witnesses.

HENRY L. HURD. Witnesses:

\VILLIAM A. COPELAND, ALICE H. MORRISON.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, .D. 0. 

